Abstract

Experiments on internal photoemission of electrons from Si and TiNx into thin Al2O3 layers suggest that crystallization of amorphousAl2O3 to the cubic γ-Al2O3 is accompanied by only a ≈ 0.5 eV upshift of the conduction band bottom edge. As it is known that in transforming from the amorphous to the γ-phase, the bandgap of Al2O3 increases from 6.2 eV to 8.7 eV, more than 80% of this gap widening must occur at the VB side of the gap. The latter suggests that interaction between electron states of O anions plays the dominant role in the oxide gap widening.